How to build a PressuVessel?

--- In spacesettlers@y..., "Combs, Mike" wrote:
> From: tomexe [mailto:tomexe@a...]
>
> the original
> Island 3 design called for windows almost 40 feet thick
>
> Is this right? Four feet I could almost buy, but 40 feet? I ask
because it
> seems like I once went back to O'Neill's original Physics Today
article
> trying to find the thickness of the glass, and couldn't find it.
>
> Regards,
>
> Mike Combs

I was suprised too, In fact the first time I saw the figures I misred
them and thought the windows were only 3m thick. But the glass panes
are built up from 3m cubes of vitreous sillica glass. They way Dyffed
Dyar wrote his page I thought that he was refering to O'Neal when he
was discussing this construction. I got it from here
http://www.dyarstraights.com/msgundam/frontier.html#OpenType

But yes, 4 LAYERS of 3m square prisms, actually not perfectly square
but slightly trapezoidal so as to form the curve, like the bricks in
a Roman arch. It doesnt need that much glass for pressure, that mass
is just for radiation and durablity over centuries. Possibly also to
handle the weight of water laying on it. Either as a resevour or just
from the accumulation of precipitation. Its a enormous amount of
glass, but when you consider the low cost of energy and transport up
there, not impossible. It would require a fairly substantial
infrastruction of glass factories and mining operations on the lunar
surface or in low lunar orbit. There is pleanty of silica and
sunlight up there. And Ti to make the frames, chosen for strength,
availablity and corosion resitance, not weight. You could use steel,
there is just as much of it on the moon, but that corrodes badly from
the atomic oxygen in the solar wind.